van gelder



(NoModeL) v 4 Sheets-Sheet 1. P. VAN GELDER.

ROLLER GRINDING MILL.

Patented Apr. 13,- 1886.

kNo Model.) 4 Sheets-Sheet 2.

' P. VAN GELDER.

ROLLER GRINDING MILL.

No. 340,019. Patented Apr.-13, 1886 X I hlesses NY PLIERS, PhuXu-Lnhogmphnr, Washinglnm u. c.

(No Model.) 4 Sheets-Sheen 3.. P. VAN GELDER.

ROLLER, GRINDING MILL. No. 340,019. Patented Apr. 13, 1886;

N. PETERS. Pholo-Lilhugmplmr, Washmgloll, n. c.

' Wzinesses: I 0) (No Model.) 4 Sheets$heet 4.

P. VAN GELDER.

ROLLER GRINDING MILL.

Z Pgbtented Apr. 13, 1886 K Jnve nior:

UNITED STATES PATENT OFFICE.

PIETER VAN GELDER, OF SOlVERBY BRIDGE, COUNTY OF YORK, ENGLAND.

ROLLER GRINDING-MILL.

SPECIFICATION forming part of Letters Patent No. 340,019, dated April 13, 1886.

Application filed December 9, 158-1. Serial No. 149,882. (No model.) Patented in England January 30, 1884, No. 2,300.

To all whom it may concern..-

Be it known that I, PIETER VAN GELDER, a subject of the King of Holland, residing at Sowerby Bridge, county of York, Kingdom of England, have invented certain new and useful Improvements in Roller GrindingMills, (for which I have received Letters Patent in Great Britain, dated January 30, 1884, No. 2,390,) of which the following is a specification.

My invention relates to roller grindingmills; and it consists in various features and details hereinafter set forth and claimed.

In the drawings, Figure l is a side view of a mill constructed in accordance with my invention; Fig. 2, a top plan view of the rollers and driving devices; Fig. 3, aside view ofthe same; Fig. 4, a vertical transverse section through the rollers; Figs. 5 and 6, views illustrating details of construction.

The surfaces of rolls driven at differential or equal speed by ordinary gearing or by obliquely-toothed or V-toothed gearing are found to assume the form of a polygon with an indefinite number of sides, showing that there is a slight slip between each tooth. To obviate this, chain-gearing and belts have both been employed; but I have found that neither of them wholly does away with the difficulty. Again, it is almost impossible to effect absolutely even feeding, and if from any cause the rolls run empty, and are allowed to touch, as is frequently the case, they grind each other and ruin their surfaces. In some cases, to prevent this, distance spacing -blocks have been inserted between the rollerhearings to keep the rolls from actually touching but as the bearings and also the journals in time wear, the distance between the centers varies, and the distance pieces or blocks become useess.

My invention is designed to avoid these evils.

Frictionpulleys are practically spurgearing with an infinite number of teeth at infinitely small distances apart,and the slip from one tooth to the next is infinitesimal or nil, and even if not ml is evenly distributed over the entire circumference of the pulley so long as its surface is truly cylindrical.

A indicates the frame of the machine, which may be of any usual and well-known construction, being provided with feed-hopper M and discharge-spouts I.

.B B B B are grinding-rolls secured upon shafts O G G 0', the ends of said shafts being provided with frictionwheels or pulleys G G G G, and supported at a point between the roll and the pulley by boxes or bearings D D D D, mounted in blocks or guides d d d (1 as clearly shown in Figs. 1, 2, and 6. The rollers B B B B are not turned truly cylindrical, but with a slightly-larger diame ter toward the center than at the ends, the difference in diameter being a few thousandths of an inch at most. This is to allow fora very slight amount of elasticity which is found to exist in the rollers and shaft, and the variation is so slight as not to be seen in the drawings. The rolls may have any required dress, according to the requirements of the material to be operated upon, and are made of chilled cast-iron, such substance being found to answer best for general milling purposes.

As already stated, the shafts 0 0'0 0 are provided with friction wheels G G G G, said wheels being secured to the shafts by means of the conical keys 9 g g g, as clearly shown in Figs. 2, 3, and 5, thus insuring the centering of the wheels upon the shafts.

The friction-wheels I make of the same material as that of which the grinding-rolls are composed-chilled cast-iron, as I find that to be a hard and homogeneous metal; and I make said friction rollers of a diameter slightly greater than that of the rolls, in order that the latter may not come into contact with each other should the feed from any cause be cut off. \Vhen the same surface-speed is desired, the pulleys on each of the shafts will both be of larger diameter than their respective rolls; but when differential surface-speed is desired one pulley must be larger than the other, care being taken, however, that the sum of their diameters be greater than the joint diameters ofthe two rolls which they drive. The friction between the driving-wheels, or the power re quired to overcome that friction, must of course exceed the power nceessaryto give motion to the grinding cylinders or rolls when in operation, or, in other words, must exceed the power necessary to overcome the resistance offered to such rotation of the rolls by the work performed. In order to provide for this excess without danger of cutting 'or abrading thefaces of the friction driving-wheels, said surface must be made of ample width to distribute the friction over a considerable surface.

WVhile it is, of course, true that within wide limits friction is proportionate to the load or pressure, regardless to the extent of surface, it is equally true that the rate of wear is affected materially by the extent of wearingsurface. In other words, wear at any point is proportionate to the friction concentrated on that point; and, appreciating these facts, I proportion the wearing-surface to the estimated wear of the grindingrolls, which latter is controlled by the character of the material and the extent or rapidity of reduction thereof for which the rolls are designed. By thus proportioning the width of the friction-wheels to the friction required, or to the pressure necessary to prod uce that friction, the desired result is perfectly attained; and in order that the wear is lightand uniform as between the friction wheels and rolls.

It will be seen that by having a series of change-wheels not only can t-he'speed of the rolls be varied as desired, but any wear that may take place can be made good by the substitution of a new wheel.

The bearings or brasses D D D D, as clearly shown in Fig. 6, are carried by boxes or blocks (1 d d (P, which are held in place by the bars A, the boxes (I (2 being movable between said arms and the boxes (1 d stationary. The boxes A are provided with slots or openings (1, adapted to receive lugs (1 projecting from the upper and lower faces of the boxes, as shown in Figs. 3, 4, and 6. The openings (2 for the lugs d of boxes D and D are made to fit the lugs accurately and prevent any sliding movement of said boxes and the rolls B B; but as saidlugs d are cylindrical in crosssection, they allow the boxes to adjust themselves to the roller-shafts, thus insuring perfect alignment, and preventing any cramping or binding action. The openings or slots d for the lugs d of boxes D D are elongated, as shown in Figs. 2, 3, 4, and 6, so as to allow a limited horizontal movement of said boxes between the bars A A when it is desired to vary the distance apart of the rolls.

To the rear or inner side of boxes D D' of the movable rolls are secured screw stems or pins 0 6 said stems being each provided with a. nut or adjustable collar, I, and with a strong spiral or volute spring, E

springs E E hear at one end against the stationary boxes D D and the other end against These the collar I, as more clearly shown in-Fig. 6,

the faces of the stationary boxes D D" being provided with seats or sockets, into'which the .ends of the springs are securely seated.- A washer is interposed between the end of the spring and the nut or collar I, and it will be readily seen that by turning the'nutor collar I in one or the other direction the spring will be compressed or allowed to expand, thereby increasing or decreasingits action. The tendency of the springs E E is to urge the mov volute spring, E or E, between the said 001- lar I and the forward or front face of the movable sliding boxes D D. The screw-stems e e, whichpass freely through the uprights,

hear at their outer ends against the shorter arm of an oscillating or rocking lever, f

pivoted to the frame at f, as shown in Figs.

3 and 4, said rocking lever f being connected to a hand-lever, F, pivoted to the frame at f, by means of a pitman or rod, f When the hand lever is moved about itsfpivot f, it

causes the short rocking or oscillating lever f to rock upon its pivot f.

Figs. 1, 3, and 4 show the levers in their difi'erent positions. The right-hand side of the machine shows the lovers in the position occupied when at work, and the left-hand side when the rolls are separated and 'at rest.

\Vhen the hand-lever F is down in position,

the upper end of lever f is thrown outward and its lower end inward against the combined action of the springs E E, acting through the screw'stems e e. The pivot con necting the hand-lever F with the link or pitman f 3 is eccentric to pivot f, as shown, and

assumes a position in line with the pivot f, so that the lever is locked in position, andany tendency of the spring to tip the leversF' and F is overcome and prevented, as will be clearly seen in Figs. 1, 3, and 4. Should at any time the feed go wrong or the rollers have to be stopped, the levers are put in the position shown at the left in Figs. 1., 3, and 4, and the springs E E, being thereby freed from the action of the levers, urge the movable roll B or 13 away from its stationary companion, B B. The two friction-rolls no longer touch each other; roll B stops, but roll B runs on and works off the accumulated feed. By simply turning the hand-leverF back to its proper position the friction wheels will again be brought into contact, and the proper motion will be thereby imparted to the rolls.

I am aware that rolls have heretofore been driven by frictional contact one with the other, and this I do not claim. Neither do I wish to be understood as claiming, broadly, the idea of driving grindingrolls by means of frictionwheels uponthe ends of the roll-shafts. Under my plan the rolls are fixed relatively to their driving mechanism, so that when in use there is no possibility of the friction-wheels becomingloose and the rolls touching. There is never under my plan any possibility of the surfaces of the rolls coming into contact, as the friction-wheels, whose combined diameters exceed those of the rolls, prevent their touching.

Another great advantage in my construction is that the friction-wheels can be removed and others substituted, in order to vary the relative speeds of the rolls as required.

Having thus described my invention, what I claim is 1. In a mill, the combination, with a frame, of a roll mounted in stationary bearings and provided at one end with a removable friction driving-wheel, a roll mounted in movable bearings, and likewise provided with a friction driving-wheel, said friction driving-wheels being of the same material as the rolls, and having a combined diameter exceeding that of the rolls.

2. Inarollergrinding-mill,the combination, with a frame, of rolls mounted therein and provided at their ends with removable friction driving-wheels of the same material as the body of the roll and of a combined diameter slightly exceeding that of the rolls.

3. Inarollergrindingmill,the combination, with a frame, of a roll carried in stationary bearings, a roll mounted in movable bearings, a spring between the roller-bearing at each end, a pin mounted in the frame, a spring encircling said pin and bearing against the front face of the movable bearing, a rocking lever hearing at one end against the pin, a handlever journaled in the frame, and a link connecting the hand-lever and the rocking lever.

4. In arollergrinding-mill, the combination, with the frame, of a roll carried in stationary bearings, a roll mounted in movable bearings, a spring interposed between the rolls at each end, a pin bearing against the outer face of the movable bearing, a rocking lever journaled in the frame and bearing at one end against the pin, a hand-lever journaled on the frame, and a link connected at one end to the pivoted lever, and at the other end to the hand-lever eecentrically, whereby the hand-lever may be made to lock the rolls in position, as shown.

5. Inarollergrinding-mill,the combination, with a frame, a roll mounted in stationary bearings, and a roll mounted in movable bearings, of springs interposed between said rolls to urge them apart, a rocking lever arranged, substantially as sl1own,to compress said spring, a hand-lever journaled in the frame, and a link connecting the hand-lever with the rocking lever.

o. In a roller grinding-mill, the combination of a pair of grinding-rolls and friction-wheels carried by said rolls and bearing directly one against the other, said friction-wheels having faces of a width determined by the character of the material to be ground by the rollers, and adapted to wear at a uniform rate therewith,whereby the relative diameters of the rolls and the friction-wheels are caused to remain always the same.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

PIETER VAN GELDER.

\Vitnesses:

VM. P. THOMPSON,- I. OWDEN OBRIEN. 

